Sports Analytics

How NBA Fans Cost Their Teams at the Free-Throw Line

Among the research showcased this week at the MIT Sloan Sports Analytics Conference in Boston—where sports nerds gather each year to parse stats in Talmudic detail—is a paper titled “Effort vs. Concentration: The Asymmetric Impact of Pressure on NBA Performance.” Behind the cryptic name is strong evidence that basketball fans have it all wrong when it comes to free-throw shooters.

Standard behavior at most college and NBA games is to make a ruckus when a player from the opposing team is at the line and to hush for players from the home team. The idea is that noise is a distraction while silence makes room for focus; the higher the stakes, the louder the ruckus or the deeper the hush. But the paper’s authors found that NBA players shoot markedly worse in pressure situations at home than they do on the road. According to Justin Rao and Matt Goldman, this is likely because the fans have it exactly backwards when it comes to adding and easing pressure.

“It seems like pretty much the worst thing you can do is have 20,000 people just look at you, hopefully, silently,” says Rao, a 29-year-old behavioral economist at Yahoo! Research. Meanwhile, “completely going crazy with all the foam fingers” seems to have no effect on shooters. Rao and Goldman looked at 300,000 free throws taken across six NBA seasons (2005-10) and found that players at home shoot nearly two percentage points worse than normal in situations when the game is on the line. Players on the road shoot about the same no matter the stakes. Crowd noise, they argue, is an everyday part of an NBA player’s life. Take it away, and players tend to get caught up in their own thoughts rather than simply going through motions they’ve practiced thousands of times. “I bet if the fans stayed completely silent for an away player,” Rao says, “that would freak him out.”

It may sound trivial, but this “home choke” effect could be costing teams seven-figure sums. According to Rao, it adds up to about one extra loss over a season, which, for a team on the brink of the playoffs (and the ticket and TV revenue that comes with) is worth about $1 million. Consider the following scenario: A player is at the line for two free throws with his team trailing by one point and a minute and half remaining. As it stands, his team has about a 30 percent of winning the game. If he makes both shots, the odds rise to about 45 percent. If even a few players are preoccupied by thousands of fans waiting to exhale, that’s a considerable advantage lost.

Basketball fans, it appears, need to learn what psychologists have long known about performing under pressure. “When you do things that distract a person, that can actually alleviate stress,” Rao says, pointing to studies on golf-putters and test-takers. Surgeons routinely use music to help ease stress in the operating room. And Hall of Fame baseball slugger Reggie Jackson famously found validation in boos. “When we go into a park on the road, people start booing me,” he told a reporter in 1974. “You don’t know how good that makes me feel. To me it means the fans recognize who I am and what I mean to my ball club. Fans don’t boo nobodies.”